Evaluation of a colorimetric method for vitamin A estimation.

Area of Science:

• Biochemistry
• Clinical Chemistry
• Analytical Chemistry

Background:

• Accurate measurement of plasma vitamin A is crucial for assessing nutritional status and diagnosing deficiencies.
• Existing spectrophotometric and spectrofluorimetric methods can be complex and require expensive equipment.
• There is a need for a simpler, more accessible method for routine vitamin A analysis.

Purpose of the Study:

• To evaluate a simple colorimetric procedure for plasma vitamin A determination.
• To compare the results of the colorimetric method with established spectrophotometric and spectrofluorimetric micro methods.
• To assess the reliability, stability, and intra-assay variation of the proposed method.

Main Methods:

• A colorimetric procedure based on the Carr-Price reaction using ferric chloride and acetyl chloride was employed.
• Vitamin A levels were determined in 30 human plasma samples and 11 rabbit liver samples.
• Results were compared against spectrophotometric and spectrofluorimetric micro methods.

Main Results:

• The colorimetric method demonstrated a high degree of correlation and good agreement with both spectrophotometric and spectrofluorimetric methods.
• Intra-assay variation was found to be 3%, which is within an acceptable range for clinical analysis.
• Reagents proved stable, allowing for sample analysis within a 4-week timeframe, unlike some alternatives.

Conclusions:

• The evaluated colorimetric procedure offers a simple, reliable, and cost-effective alternative for plasma vitamin A measurement.
• This method does not require sophisticated or expensive equipment, making it suitable for wider application.
• The stability of reagents and acceptable intra-assay variation support its utility in clinical settings.